Magnetodielectric Effect in Crystals of the Noncentrosymmetric CaOFeS at Low Temperature

Abstract

Single crystals of the stoichiometric iron calcium oxysulfide CaOFeS have been grown by a solid-state reaction. Structural analysis of CaOFeS at room temperature by combining single-crystal X-ray diffraction data and transmission electron microscopy leads to a stoichiometric hexagonal noncentrosymmetric P63mc layered structure isostructural to CaOZnS. It is built from alternating layers made of FeOS3 tetrahedra sharing sulfur apexes and stacked with Ca(2+) planes. All Fe-O bonds are parallel to the stacking axis; this breaks the centrosymmetry, leading to a polar structure. The dielectric measurements reveal the existence of a magnetodielectric effect near 33 K in good agreement with the Neel temperature, as evidenced near 35 K by specific heat measurements reported by a different group.

Exchange striction driven magnetodielectric effect and potential photovoltaic effect in polar CaOFeS

“…Experimentally, the magnetodielectric effect is observed around the AFM T N [13], which can also be understood by the following analysis and DFT calculation.…”

“…The change of polarization (∆P ) calculated is along the c-axis, which is 1.94 µC/cm 2 at U eff = 2 eV and decreasing with U eff (Fig.5). Such a ∆P is considerable large for magnetodielectric effect, reflecting by a dielectric peak around T N as observed in experiment [13]. In addition, our calculation proposes to perform the pyroelectricity measurement, which should observe a pyroelectric current peak around T N .…”

“…For example, CaOM S (M =Fe, Zn) forms layered triangular lattice [10][11][12][13]. As sketched in Fig.…”

The Ternary Post‐transition Metal Carbodiimide SrZn(NCN)2

“…Although not directly relatable topologically, the oxysulfides SrZnSO, CaZnSO, CaCoSO, and CaFeSO are of interest as they feature tetrahedral M 2+ coordination spheres and layered cation ordering similar to that in SrZn(NCN) 2 . The presence of hexagonal arrays of both oxide and sulfide, however, generate a pseudo‐octahedral site for Sr/Ca in a non‐centrosymmetric P 6 3 mc structure, which affords a variety of interesting physical properties . An obvious future goal is, thus, to access similar structures in cyanamide analogues through the compositional tuning of the alkaline‐earth and transition metal species.…”

Spin-polarized Second Harmonic Generation from the Antiferromagnetic CaCoSO Single Crystal

“…. It has been reported that the CaCoSO is isostructural with CaZnSO, BaCoSO and CaFeSO3637383940. Since the newly synthesized CaCoSO crystallizes in non-centro-symmetry, this results in the loss of inversion symmetry, which in turn gives a considerable SHG.…”